Feb. 13, 2013 -- A new illness similar to the deadly SARS virus has probably spread from person to person in the U.K.

Previous cases of this new virus, a coronavirus, have been seen in people who've returned from visits abroad. The latest case is in a person who hasn't been abroad recently and is thought to have caught it from a relative, British officials say.

However, officials say the threat of the infection spreading remains very low.

Coronaviruses

Many coronaviruses are not a cause for concern. Some strains cause the common cold but also include SARS, or severe acute respiratory syndrome.

The new coronavirus was identified in September 2012 in a person who died from a severe infection of the lungs. The virus caused fever, cough, shortness of breath, and breathing problems.

British officials say 11 confirmed cases have been seen worldwide, including three deaths in Saudi Arabia and two deaths in Jordan. None have been reported in the U.S., according to the CDC.

Previous U.K. cases have been seen in people who travelled to Qatar, Pakistan, and Saudi Arabia.

Person-to-Person Transmission?

Officials say two new cases were found in a U.K. resident who had recently been to the Middle East and Pakistan and a family member who had not traveled recently. They are in intensive care at the Queen Elizabeth Hospital in Birmingham. The family member has an existing medical condition that makes them more susceptible to infections of the lungs, officials say.

In a statement, Professor John Watson, head of the respiratory diseases department at Britain's Health Protection Agency (HPA), says, "Confirmed novel coronavirus infection in a person without travel history to the Middle East suggests that person-to-person transmission has occurred, and that it occurred in the U.K.

"Although this case provides strong evidence for person-to-person transmission, the risk of infection in most circumstances is still considered to be very low. If novel coronavirus were more infectious, we would have expected to have seen a larger number of cases than we have seen since the first case was reported three months ago."

The HPA says special measures have been put in place to stop the infection from spreading.